Influence of argon neutral beam energy on the structural properties of amorphous carbon thin films grown by neutral particle beam assisted sputtering

Abstract

The effects of argon neutral beam (NB) energy on amorphous carbon (a-C) films were investigated, the a-C films were deposited by a neutral particle beam assisted sputtering (NBAS) system. The energy of the neutral particle beam can be directly controlled by a reflector bias voltage as a unique operating parameter of the system. The results from the analysis by Raman spectra, Fourier transform infrared (FT-IR). UV-visible spectroscopy and electrical conductivity indicate the properties of the amorphous carbon films can be manipulated by simply adjusting the NB energy (or reflector bias voltage) without changing any other process parameters. By increasing the reflector bias voltage, the amount of cross-linked sp(2) clusters as well as the sp(3) bonding in the a-C film coating from the NBAS system can be increased effectively and the composition of carbon thin films can be changed from a nano-crystalline graphite phase to an amorphous carbon phase. In addition, the deposition rate increases with reflector bias voltage due to additional sputtering at the carbon reflector without any variation of physical and electrical properties of the a-C film. (C) 2011 Elsevier B.V. All rights reserved.